Mar 25, 2013

F.D.A. Approves “Flublok” Vaccine: New Insect-Based Flu Vaccine

Via: TheNews
The U.S. Food and Drug Administration (F.D.A.) gave regulatory approval to a new influenza vaccine called Flublok on Wednesday, January 16. Flublok is produced by Protein Sciences, a small company based in Meriden, CT, and serves as the world’s first highly purified, egg-free, recombinant flu vaccine. “We’re very pleased with the FDA approval because it validates our platform technology,” said Dr. Penny Post, Vice President of Regulatory at Protein Sciences and wife of Choate science teacher Mr. Deron Chang, on behalf of the company. “Flublok represents the next step in improving the technology for vaccine development.”

Dr. Post’s Background

With a strong background in biochemistry and cell biology, Dr. Post first joined Protein Sciences Corporation in April of 2000. She has since then held management positions in the company’s Process Development, Manufacturing, Quality Control, and Quality Assurance departments, according to the Protein Sciences website.

Promoted to Vice President of Regulatory in 2011, Dr. Post served as the liaison between Protein Sciences and the F.D.A. in the final stages of Flubok’s development and approval. “Starting from 2003 until today, Protein Sciences did all the final development of the product, and I’ve been involved in every department,” said Dr. Post. “It’s rare for a scientist to be able to be part of bringing a product to market… this is definitely the most significant accomplishment in my career to date.”

Although Protein Sciences was on the verge of bankruptcy in 2009, the company won a $147 million contract from the U.S. Department of Health and Human Services to develop Flublok, according to an article published in The New York Times on June 23, 2009.

Current Flu Season

Regulatory approval of the new influenza vaccine is welcomed amidst one of the most austere flu seasons in recent memory. According to the Centers for Disease Control and Prevention, over 129 million flu vaccines have been distributed so far this year in the United States, and many Americans are searching for the remaining stock as the number of ready-made doses continues to dwindle.

Yet Dr. Post maintains that the timing of Flublok’s approval has no correlation with the present flu season conditions. “Everything is on a specific timetable with the FDA from when you file your license,” she said. “We filed information in July for Flublok which we knew was going to be the last piece that the F.D.A. required prior to approval, and at that point we knew they had until January 16th to finish reviewing that information.”  

“It’s just incredible timing that it ended up being a really bad flu season, and then our vaccine is approved right in the middle of it,” Dr. Post added.
According to the F.D.A. website, flu vaccinations are traditionally developed by inoculating fertilized chicken eggs with the influenza virus. After several days of amplification, the virus is then inactivated and purified. Such a process is done months before a vaccination’s intended flu season and may leave behind traces of viral as well as egg proteins in the final product. A frequent problem with the egg-based vaccine, Dr. Post noted, is that “the strains represented in the vaccine are often times different from the viral strains making people sick because the egg process is a relatively long method of production.” Because flu strains in circulation are constantly evolving, a vaccine produced months in advance of its intended use may not produce the correct protective antibodies required to subdue a changed virus.

An Egg-Free Vaccination

However, Flublok, Ms. Post explained is comprised of hemagglutinin, a surface influenza virus protein derived from the genetic engineering of a baculovirus. Dr. Post explained that to make the protein-based vaccine, genetic information for hemagglutinin is put into the baculovirus, which then infects fall armyworm insect cells. “The virus uses all of the cell’s machinery to manufacture the protein we want,” she said. “The cells grow in a bioreactor to make a large batch of hemagglutinin, and then the protein goes through a purification process that removes all the insect and viral proteins that we don’t want.”

Although the manufacture of Flublok requires the use of a live virus, Dr. Post asserts that the vaccine’s production platform nurtures a safe final product. “The baculovirus can only infect the insect cells; it can’t infect mammals, and it can’t infect and replicate in humans,” she commented. “So it’s a very safe platform… it’s not something that poses a danger to humans.”

Because of the trace amounts of egg protein in standard influenza vaccines, Flublok serves a safer alternative to those with egg related allergies. In addition, the modern recombinant DNA technology involved in the product’s production, which does not depend on egg supplies, allows for a faster development of vaccinations for seasonal uses and in cases of pandemics.

Yet the F.D.A. kept a close eye on Protein Sciences’ use of recombinant technology during the Flublok project. Despite having approved two other vaccines using the same methods employed by the company, the F.D.A. still considers the usage of insect cells as a “novel cell substrate” for vaccine production, according to the F.D.A. website. “One of the hurdles to the project was completing the qualification of our cell substrate to F.D.A. satisfaction,” said Dr. Post. “We had to do extensive testing to show that this [Flublok] is safe for humans.”

Protein Sciences has manufactured 150,000 2012-2013 composition Flublok vaccines ready for distribution. Although the vaccine is approved only for adults 18-49 years old, it has, received praise from the federal government. In a statement released on January 18, Assistant Secretary for Preparedness and Response (ASPR), Nicole Lurie, stated, “Our nation has reached a landmark in influenza vaccine history with the U.S. Food and Drug Administration’s approval of a new seasonal flu vaccine, called Flublok, made with novel technology…. The approval…of the new vaccine produced with this modern technology stands as one of the most significant improvements in flu vaccine technology in the past 50 years.”
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